Population Structure and Seed Productivity of Dactylorhiza incarnata (L.) Soó (Orchidaceae, Liliopsida) at the Northern Border of Its Habitat

—Populations of the rare orchid Dactylorhiza incarnata (L.) Soó have been studied at the northern border of the species habitat in the Komi Republic (northeast of European Russia). Data on the population structure, morphometric traits of plants, and reproductive characteristics of the species are given. According to the results obtained, the size of plants of this species and the number of flowers per inflorescence in the region is lower than those in more southerly areas. The population size varies within 30–350 plants with an average density of 0.7–3.7 plant/m 2 . The reproductive success is associated with the weather conditions of the second ten-day period of June (time of flowering of this species in the region). The size of D. incarnata seeds (0.55 × 0.20 mm, on average) at the northern border of the species habitat is smaller than in other areas. Seed productivity is rather high: one fruit contains 6200 seeds, on average, and the real productivity of an individual plant is ~49 400 of seeds. Seed quality depends on the weather conditions including the temperature during flowering and the amount of precipitation during seed formation. The presence of juvenile plants in all populations studied indicates successful seed reproduction of the species at the northern border of its habitat despite decreased seed productivity compared to southern populations.